Effect of α-chymotrypsin on breaking strength and ultrastructural morphology of canine ciliary zonules

Abstract

Objective-To determine the effect of α-chymotrypsin treatment on breaking strength and ultrastructural morphology of canine ciliary zonules. Sample Population-Eyes from young randomsource dogs from an animal shelter. Procedure-Eyes were obtained immediately after euthanasia of dogs. The enzyme α-chymotrypsin was applied to the ciliary zonules of 1 eye of each dog; the other eye was treated with saline solution as a control. The breaking strength of ciliary zonules was measured, using a linear actuator and force transducer. The lenses and ciliary bodies were then analyzed by scanning and transmission electron microscopy. Results-α-Chymotrypsin reduced the breaking strength of ciliary zonules by a mean ± SD 44 (± 20)%, compared with that for saline-treated control eyes. Increasing the volume of enzyme further decreased the breaking strength of the zonules. Differences in the appearance of the ciliary body by electron microscopy were not apparent between enzyme- and saline-treated specimens. Conclusion and Clinical Relevance-Application of α-chymotrypsin to enucleated canine eyes at a Concentration used in people significantly reduces the breaking strength of canine ciliary zonules without any apparent damage to the ciliary body. α- Chymotrypsin may be useful in the removal of subluxated canine lenses and in removal of cataractous lenses in young dogs, in which phacoemulsification often results in appreciable post operative capsular opacification.